This invention relates to novel ordered copolyetherketones and, more precisely, to copolymers of tere- and isophthalyl halides with diphenyl ether where the phthalyl groups alternate or where the terephthalyl or isophthalyl groups are in blocks. The invention also relates to processes for preparing the novel copolyetherketones and to shaped articles and composite structures containing them. The invention also relates to blends of the novel copolyetherketones with other polymers and, especially, with certain polyetherimides.
Random copolymers of tere- and isophthalyl chloride with diphenyl ether are known in the art. U.S. Pat. Nos. 3,516,966 and 3,637,592, issued to Berr on June 23, 1970, and Jan. 25, 1972, respectively, disclose crystalline copolyketones having the following repeating structural unit ##STR1## Both patents disclose that the copolyketones may be prepared by combining diphenyl ether and a mixture of terephthalyl halide and isophthalyl halide with a Friedel-Crafts catalyst such as boron trifluoride. Such reactions are further described in U.S. Pat. No. 3,441,538, issued to Marks on Apr. 29, 1969. An improvement in the process, which allows formation of a granular product, is disclosed in U.S. Pat. No. 3,791,890, issued to Gander et al. on Feb. 12, 1974.
A number of varied uses for the known diphenyl ether/tere- and isophthalyl halide copolymers have also been disclosed. U.S. Pat. No. 3,666,612, issued to Angelo on May 30, 1972, discloses heat-sealable copolyketone film structures consisting of a crystalline layer and an amorphous layer, both layers being comprised of copolyxers of diphenyl ether and tere- and isophthalyl halides. U.S. Pat. No. 3,674,627, issued to Angelo on July 4, 1972, discloses the use of films of copolymers of diphenyl ether and tere- and isophthalyl halides as insulation wrapping for electrical conductors. And U.S. Pat. No. 3,668,057, issued to Agolini et al. on June 6, 1972, discloses laminar structures comprising a layer of metal bonded to a layer of crystalline diphenyl ether/tere- and isophthalyl halide copolymer.
Although the above-cited patents disclose copolymers of diphenyl ether and tere- and isophthalyl halides, they disclose only random copolymers, i.e., copolymers in which the tere- and isophthalyl units are randomly dispersed along the backbone of the polymer chain. These random copolyetherketones were of limited utility for a number of reasons. At higher ratios of terephthalyl (T) content to isophthalyl (I) content, the melting point of the copolyetherketone tended to be too high and instability set in. Conversely, at lower T/I ratios, where the melting point dropped off, so too did the retention of physical properties at elevated temperatures. Thus, upper use temperatures for such copolyetherketones were too low. Also, at lower T/I ratios, the degree of crystallinity of the copolyetherketones decreased, and they became more sensitive to solvents and stress cracking. Finally the propensity of the random copolyetherketones to crystallize was poor. This required long hold times during molding to allow the attainable level of crystallinity to develop.